On Tuesday, we told you about the 70 activists who poured onto two nuclear sites in Sweden in an effort to show how lax the security is at these plants.

We didn’t tell you that at least six of them hid overnight at two of the plants: four at Ringhals and two at Forsmark.

They evaded security all night, and were only discovered when Greenpeace Sweden phoned the media early this morning to reveal their presence at the plants. This is despite the fact the operator Vattenfall said yesterday that “security had worked exactly as intended”. Oh dear.

One of the overnighters was Greenpeace International energy campaigner Lauri Myllyvirta. Here’s what he wrote about the experience:

“I’ve spent the night on the roof of the Swedish nuclear power plant Ringhals. More than 24 hours – and I’m only out because we chose to reveal our presence here.

That shows me, how alarmingly easy it is to access the vital systems that supply the reactor cooling systems with power.

The recent report on the EU stress tests revealed that in some Swedish reactors, a loss of power to the reactor would lead to a nuclear accident in just one hour.

I took part in this demonstration to draw attention to how little nuclear companies care about the health and safety of people, and how little they do to protect reactors from accidents.

The gaps in safety recently revealed about Swedish nuclear reactors are an absolute disgrace and a cause for alarm. Nuclear operators have not prepared for obstruction of seawater cooling, for snowfall or earthquakes of a magnitude that can occur in Sweden.

The failure of back-up generators and several other safety systems in Forsmark in 2006 were some of the most serious near misses since 2000, before the Fukushima disaster.

The authorities have tried to access the safety violations for years through soft measures: special surveillance, reports, investigations and revised protocols.

Still, blatant security problems continue. The latest evidence was a fire at Ringhals just a few months ago due to a rushed start-up procedure. An intentional cover-up followed.

The only way to end this continuous cutting of corners before a serious accident happens is for violations to have clear consequences: the offending operators need to have their reactors taken offline, at least until the worst issues have been addressed.

The Swedish environmental minister has called the operators in Sweden, E.oN and Vattenfall, to her office today, based on this Greenpeace action, and she has publicly threatened them with revoking the operational license permit if they cannot fix the problems we have highlighted. I hope she sticks to that threat and free Sweden from dangerous, expensive and unnecessary nuclear power."

We wonder what Sweden’s environment minister is thinking today, now that she has learned about Greenpeace activists evading security at two nuclear sites for more than a day.

UPDATE: It turns out there were two more activists than the nuclear facility operator thought! They were never found, but turned themselves in after 38 hours.

I understand why so many people are agitated by this, and I largely agree with you that the security is a major issue at many nuclear power plants. Bu...

I understand why so many people are agitated by this, and I largely agree with you that the security is a major issue at many nuclear power plants. But let's say we get them all closed down within a week, what should replace fill the gap of the energy previously produced by these power plants?

Exploitation of the few rivers and streams left to create more hydroelectric power stations that will do additional harm on our environment. Or should we use (heaven forbid) coal power plants?

I believe some people might need to rethink a little, although the ground thought is good.

The story is just full of nonsense. None of the people actually made it inside or was even close to be inside.
Greenpeace seems to have only strong opinions against the things they consider to be wrong, without bringing on alternatives. Suggesting to take away a licence to operate is so stupid and naive, since it will bring enormous despair to poor people in the country, due to a enormous raise of power prices in case of a shut down. So, in stead of reacting how great this action is, people should think rather then follow some stupid activist nonsense talk.

@Lovahaisa and @Erik2: Greenpeace has not only thought about the alternatives, but also delivered a detailed calculated Energy [R]evolution Scenario, ...

@Lovahaisa and @Erik2: Greenpeace has not only thought about the alternatives, but also delivered a detailed calculated Energy [R]evolution Scenario, that offers the policies that need to be followed for a clean and safe energy future - on global, regional and for many country national levels. You can find them on http://www.energyblueprint. info.

@ NuclearForFutureEnergySecurity - Grow up nuclear lobby - do you really need people who go intelligently further than we have done during this action...

@ NuclearForFutureEnergySecurity - Grow up nuclear lobby - do you really need people who go intelligently further than we have done during this action to make the point that security never can be sufficient? Apart from the fact that some people were in areas that are of high concern from a security and nuclear safety perspective, like the emergency diesel generator area.
Nuclear power stations are too large a risk to continue to take when cheaper and cleaner alternatives are available that also deliver faster. They can be phased out without hurting the economy at large (see the Greenpeace / EREC energy [r]evolution studies on http://www.energyblueprint.info).

So, you have one or more people in ONE of the emergency diesel generator rooms. What about the other back up system areas,...

@Jan Haverkamp

So, you have one or more people in ONE of the emergency diesel generator rooms. What about the other back up system areas, the multiple diverse, redundant and segregated operating and safety sytems and the fact that even if you coculd take out all of these systems and cause a loss of cooling event, you'd still need to breach containment to create a release to the environment. This threat does not exist.

It is absolutely obscene that there are more nuclear reactors being built based upon Zirconia-clad fuel rods which are hugely inefficient in their use...

It is absolutely obscene that there are more nuclear reactors being built based upon Zirconia-clad fuel rods which are hugely inefficient in their use of radioactive fuel pellets, generate vast quantities of highly dangerous nuclear waste that must be stored for thousands of years, and become uncontrollable in a core metl-down scenario. The only type of nuclear power that should be used at all is Thorium LFTR because it allows existing stockpiles of nuclear waste to be safely "burnt up", thereby ridding the environment of the insane and obscene legacy of conventional contemporary nuclear power. When I raised this with IAEA, I was merely belittled and talked down to. This makes me very very angry. Has the IAEA no consicnece, no sence !? Thorium LFTR, else solar/wave/tidal/wind/geothermal. Geothermal benefits from the natural nuclear reaction occurring in the core of the Earth, driven largely by Thorium transmutation to Uranium 233 undergoing fission reactions. Under our feet, in the core of the Earth, and above our heads in the Sun, are natural nuclear reactions. However, all this Plutonium, MOX and similar ghastly technology, especially when using solid fuel rods, is not natural and has created a huge problem for humanity. The people responsible for contemporary nuclear system should be punished for their negligence and stupidity.

Do you have any idea how irresponsible this action was. You could have taken a terrorist with you, and no doubt if something had gone wrong, you’d hav...

Do you have any idea how irresponsible this action was. You could have taken a terrorist with you, and no doubt if something had gone wrong, you’d have blamed them instead of yourselves. Well done. I’m just going to go let the Taliban know that if they join you, they’ll get to go play at nuclear power plants.

Do people really wonder why greenpeace is ignored by industry when this kind of thing happens. Let me make some things clear, the nuclear industry has...

Do people really wonder why greenpeace is ignored by industry when this kind of thing happens. Let me make some things clear, the nuclear industry has few deaths and injuries than any other power generation company. I realize that many will not believe this but the statistics are there for all to read.

I dont think people understand how clever the people who work in these plants are. Backup generators are stored securely and are diesel powered in order to cool the reactor in the event of power outage. Yes there was lax security there and that is unacceptable but bash a whole industry that you nothing about because of 1 incident.